Electromagnetic Induction Quiz

A circular loop of radius 2cm, is placed in a time varing magnetic field with rate of 2T/sec. Then induced electric field in this loop will be

• 0.4V

• 0.04 V

• 4 mV

• 0.12 V

In an L -R circuit, time constant is that time in which current grows from zero to the value (Where is the steady state current):

• 0.63

• 0.50

• 0.371

Flux linked through following coils changes with respect to time then for which coil an e.m.f. is not induced:-

• Copper coils

• Wood coil

• Iron coil

• None

An L-R circuit consists of an inductance of 8mH and a resistance of 42. The time constant of the circuit is

• 2ms

• 12ms

• 32ms

• 500 s

A coil of inductance 2 Hhas a current of 5.8 A. The flux in weber through the coil is -

• 0.29

• 2.9

• 3.12

• 11.6

A solenoid have the self inductance 2H. If length of the solenoid is doubled having turn density and area constant then new self inductance is :

• 4H

• 1H

• 8H

• 0.5 H

The value of self inductance of a coil is 5H. The value of current changes from 1A to 2A in 5 sec., then value of induced emf in it -

• 10V

• 0.1V

• 1.0V

• 100V

For a coil having L = 2mH, current flow through it is I = tet then the time at which emf becomes zero:-

• 2 sec.

• 1 sec.

• 4 sec.

• 3 sec.

A solenoid wound over a rectangular frame. If all the linear dimensions of the frame are increased by a factor 3 and the number of turns per unit length remains the same, the self inductance increased by a factor of -

• 3

• 9

• 227

• 63

A coil of self inductance 2H carries a 2A current. If direction of current is reversed in 1 sec., then induced emt in it -

• - 8V

• 8V

• - 4V

• Zero